State of Guerrero.
My wife and I were last on the "Coquette Road" in May 1994. The road recently had been paved to San Vincente ("Vicente" on one map), allowing easy access to the area. Likely a result of this "improvement," we noted more habitat destruction than when we were there in December 1993.
The proper (unsigned) road is reached by exiting the northeast ("far right") corner of Atoyac; go north at least to the central church before you head east. (As a marker, just out of town is a small building on the right labeled "Jardin de Ninos.") Driving time was about 45 minutes between Atoyac and San Vincente; it took about 90 minutes to reach Atoyac from the east side of Acapulco.
Just north of San Vincente is a small bridge. We had a male coquette 0.4 km north of this bridge May 15, and a female 3.2 km beyond the bridge on a return visit two days later. In both December and May, the best general birding (at least up to Paraiso) was in the area of a ridge crest 4.4 km north of the bridge.
Greg D. Jackson